runtime

README

Runtime Module

The runtime module provides the execution environment and runtime services for opal commands and decorators.

Purpose

This module contains the runtime infrastructure that powers opal execution:

• Execution Context: Runtime environment for command execution
• Decorator Registry: Registration and lookup system for all decorators
• Decorator Interfaces: Abstract interfaces that all decorators must implement

Key Components

Execution Package (runtime/execution/)

• context.go: Execution context providing variables, shell execution, and decorator services
• types.go: Execution result types and execution mode definitions
• shell_test.go: Tests for shell execution functionality

Decorators Package (runtime/decorators/)

• interfaces.go: Core decorator interfaces (FunctionDecorator, BlockDecorator, PatternDecorator)
• registry.go: Global decorator registration and lookup system

Registry Package (runtime/registry/)

• Future home for additional registry services

Module Dependencies

• Depends on: core module for AST types and plan structures
• Used by: cli module for decorator implementations and execution
• External: No external dependencies beyond Go standard library

Architecture

Execution Modes

1. InterpreterMode: Direct execution of commands
2. GeneratorMode: Code generation for standalone binaries
3. PlanMode: Dry-run plan generation for visualization

Decorator System

The runtime provides a unified decorator system where:

• Value decorators expand inline (e.g., @var.name, @env.PORT)
• Execution decorators wrap command blocks (e.g., @timeout{}, @retry{}, @parallel{})

Usage

import "github.com/opal-lang/opal/runtime/execution"
import "github.com/opal-lang/opal/runtime/decorators"

// Register a new decorator
decorators.RegisterFunction(&MyDecorator{})

// Create execution context
ctx := execution.NewContext(program)

Design Principles

• Mode-agnostic: Decorators work across interpreter, generator, and plan modes
• Extensible: Easy to add new decorators without modifying core runtime
• Safe: Proper isolation and error handling for decorator execution
• Performance: Efficient execution with minimal overhead